The cage should be large enough for the cavy to exercise freely. It should be at least 16" x 24" for a single animal. Cavies love to run and jump when they are healthy and happy. Some enjoy running through a large, empty oatmeal box (with ends removed) or sitting on a block of wood. Cavies are very clean and odorless if kept on clean bedding. Cavies must never be kept on wire! Wire bottoms on cages will cause foot infections and broken legs. If your cage has a wire bottom, cover the wire with newspaper, then cover the newspaper with shavings. The cage should be changed at least twice a week. Masking tape around the bottom sides of the cage will keep the shavings or droppings from flying out as your pet plays. Deep trays work best.
Hang a water bottle on the side of the cage and change the water at least once a day. Clean bottle with a mild bleach solution once a week.
A good, fresh cavy pellet is necessary to give the cavy all the nutrition it needs to grow strong and stay healthy. Never purchase packaged "guinea pig food" off a shelf. Chances are it will be so old that all the food value will be gone and your cavy will slowly die from malnutrition. Feed stores and reputable pet stores will purchase a good cavy pellet and supply it in bulk form. Don't over-buy. Remember, old food is worthless. If you can't get good quality cavy pellets, use a good quality rabbit pellet and add a flavored vitamin C tablet to the drinking water each day.
Cavies, like humans, do not produce the C vitamin and it is essential to their health and well-being to have vitamin C supplied in their diet. A quarter of a fresh orange per cavy every day is also a good way to supply vitamin C. Cavies will eat many fruits and vegetables so you can introduce your cavy to a variety and learn its likes and dislikes. Your lawn may provide an excellent source of vitamin C in the dandelion plant. This plant should be offered only if you do not use pesticides or other harmful chemicals on your lawn.
Alfalfa hay cubes are good to keep in the cage at all times for snacks and chewing exercise for the teeth which are growing continually and need the chewing to keep them from overgrowing. Overgrown teeth means the cavy cannot eat properly and they will starve if the teeth are not trimmed.
You can bathe a cavy with a mild shampoo (diluted half and half with water). Towel dry, or, if the weather is cool, use a blow dryer. Comb or brush their hair in the direction it grows - forward for Peruvians, backwards for the other breeds. Clip toenails occasionally. You may spray their coats with a flea and lice spray made for cats and kittens, hamsters or birds. If you let your cavy run on the lawn they may pick up lice from bird droppings in the grass. A quick spray and brushing usually takes care of any problem. These lice are NOT transferable to humans.
Cavies, given the proper food and care, are very hardy little animals and can live five to seven years. The biggest health hazard to a pet cavy is the human cold. If you have a cold give your cavy extra vitamin C and stay away from your pet! Do not cough or sneeze near your cavy and if you must handle your pet, wash your hands first. Never put your cavy in direct sunlight! Heat kills! Cavies have an internal body temperature higher than most animals and overheat quickly. Remember, heat stroke kills quickly! A cavy, unlike many animals, cannot transmit any disease to you.